Gallium-nitride (GaN) is a commonly used Group IIIA-N material, where Group IIIA elements such as Ga (as well as boron, aluminum, indium, and thallium) are also sometimes referred to as Group 13 elements. GaN is a binary IIIA/V direct bandgap semiconductor that has a Wurtzite crystal structure. Its relatively wide band gap of 3.4 eV at room temperature (vs. 1.1 eV for silicon) affords it special properties for a wide variety of applications in optoelectronics, as well as high-power and high-frequency electronic devices.
One of the major factors that can limit the performance and reliability of Group IIIA-N based high-electron-mobility-transistors (HEMTs) is their relatively high gate leakage. The gate leakage can reduce the breakdown voltage and the power-added efficiency while increasing the noise figure. To help reduce the gate leakage problem, some have changed the gate dielectric material from conventional SiN or SiON or to other dielectric materials, or to multi-layer gate dielectric stacks.